1. Technical Field of the Invention
The invention relates to a residue collector for the collection of residual liquid in a low-pressure tube, which extends vertically or inclined, consisting of two adjoining pipe nozzles, the interior spaces of which are in mutual connection and form a cavity, which, via an orifice, can be connected to a portion of the low-pressure tube, which extends upwardly, and can be connected via a lower orifice to a downwardly extended portion of the low-pressure tube.
2. Description of the Prior Art
In tubes via which liquid or a mixture of air and liquid is sucked certain residues always remain after the low pressure is disconnected. These residues are much greater in a corrugated tube or in a tube that is reinforced with ribs or with a spirally winding rib than with smooth tubes, and often lead to the very troublesome effect that the last residue of the liquid that was just sucked in runs out again when the low-pressure is switched off. This effect occurs in particular in the case of perpendicularly extending tubes, but even with only slightly inclined tubes.
In the prior art, to remedy this problem, flap valves are known, which seal the suction orifice in a liquid-tight manner briefly before the low pressure is switched off, and thereby prevent any liquids running back from escaping. However, the disadvantage is not only the increased installation work for the flaps and the additional work for controlling the flap, but also the necessity to dispose of the liquid that has collected above the flap in an additional operation with an additional trap vessel.
Another problem solution that is widely known in the prior art is the siphon, as S-shaped pipe section, the downwardly pointing bend of which is so strongly curved that the liquid is deposited therein and can no longer flow out. If such a siphon is unfilled when the low pressure is switched off, residual liquids that are still located in the tube can collect therein.
The disadvantage however is that with the restoration of the low pressure, the tube is sealed off in an airtight manner by the liquid in the siphon, so that the suction pump must at first build up a subatmospheric pressure high enough to move the entire liquid out of the siphon tube. Only then can the low-pressure tube take up liquid from the outside again.
The smaller the radius of curvature of the siphon bend is chosen—for a constant diameter of the tube—the smaller the amount of liquid is stored therein, and therefore the lower the threshold value of the low pressure before the first suction. With such a strongly curved siphon, however, its increased flow resistance is disadvantageous, specifically during continuous operation, whereas a siphon with a very large radius of curvature only requires a high low-pressure value on start-up and generates only a small flow resistance.